Jearranaikarn W, Siwadune T. A Comparison of Cervical Ruler and Transvaginal Ultrasound for Cervical Length Measurement during Pregnancy. Thai J Obstet Gynaecol [internet]. 2021 Mar. 1 [cited 2026 Sep. 24];29(2):65-72. available from: https://he02.tci-thaijo.org/index.php/tjog/article/view/218988